This invention relates to a platform shaker in three dimensional motion, whose platform can move both forward/backward and left/right from its central position, swirl in a nutating rotational motion, maintain the horizontal level even when the operation of the platform shaker is halted, and operate with an adjustable mechanism to control the magnitude of the nutating rotational motion. Hence such platform shaker can be applied to analyses including DNA extractions, hybridizations, and gel staining in genetics, biology, and molecular biology by stirring samples which are mounted on the described platform. The platform shaker in three dimensional motion of this invention is particularly appropriate for DNA extractions because the tilt angle of the platform as well as the nutation rate can adjust according to characteristics of DNA's to provide for a small tilt angle and a fast nutation rate for a short chain DNA and for a large angle and a slow nutation rate for a long chain DNA.
The novel platform shaker in three dimensional motion can also be used for many other purposes including paper making by attaching a small paper making apparatus onto the platform, and stirring or mixing pieces of soft agar placed in a laboratory dish because the platform shaker can be operated in a nutating rotational motion and halted keeping the level of the platform horizontal.
FIG. 8 shows an embodiment of a conventional platform shaker with existing technology, which includes a motor 7 at the bottom of a box 1 and a horizontal cylindrical rotor 2 attached at the center of the bottom surface to the upward rotational axis 7a of the motor 7 directly below the aperture la located at the center of the top surface of the box 1. A straight hole with a finite depth 3 is drilled on the top surface of the horizontal rotor 2, into which the lower end of the nutating rotational rod 4 whose diameter is smaller than that of the straight hole 3 is inserted. The described nutating rotational rod 4 is supported by a bearing 5 of two, mutually fitting cylindrical parts in the middle portion of the nutating rotational rod 4 and also aligned approximately with the center of the horizontal cylindrical rotor 2. The described bearing 5 is fixed with an angled plate 8, which is fixed inside the box 1, through a support extension 5a to the angled plate 8. The upper end of the nutating rotational rod 4 points upward to the aperture 1a of the box 1, and is attached by inserting into the support unit 4a in order to hold the center of the platform 6 which is a flat and rectangular shape. The unit 9 is a stopper mechanism which causes the previously described nutating rotational rod 4 to nutate without self-axial rotational motions. The stopper mechanism consists of the stopper rod 9a which is fixed at the middle of the nutating rotational rod 4, and a framed piece 9b which is attached to the box 1. The stopper rod connects with the frame piece in a manner that allows the vertical oscillatory motion and simultaneously prevents a horizontal oscillatory motion of the stopper rod 9a.
With the conventional platform shaker described above, the platform 6 is tilted even when the platform shaker is halted, and hence it is impossible to keep the horizontal level of the surface of a liquid sample mounted on the platform 6 after stirring.
Also, it is impossible for the conventional platform shaker to continuously change the magnitude of the nutating rotational motion of the platform while it is being operated.
The platform shaker in three dimensional motion of this invention is designed to have capabilities of maintaining the horizontal level of the platform when the nutating motion of the platform is halted, and hence keeping the surface of a sample level after stirring. This invention also provides for changing the magnitude of the nutating rotational motion in a continuous manner while the shaker is being operated.